The present invention relates to a carbon-containing ribbon wrapped about a carbon brake disk core to form an outer layer. The ribbon, which contains a bonding agent either through preimpregnation or through the application of a bonding compound after the wrapping, is pyrolyzed so that an integral brake disk is formed.
Heretofore, carbon brake disks have been made of carbon or graphite-based materials. However, all such brake disk constructions had generally utilized some type of reinforcement, invariably carbon filaments in some fabric form such as cloth, woven material, etc. Usually, the brake disk was made by cutting the fabric in the form of an annulus, forming a stack by piling a plurality of said annulus on the top of the preceding annulus, impregnating the stack with a bonding agent according to any conventional method, and pyrolyzing the stack to produce a carbon brake disk. Usually, the impregnation step was repeated a number of times until all of the pores within the stack were generally filled or until a desired density was obtained, as set forth in U.S. Pat. No. 3,794,509. Although a relatively good brake disk was produced, this method was time consuming and costly.
Another somewhat similar method is set forth in U.S. Pat. No. 3,730,320 to Freeder et al. In this patent, segments of an annular carbon cloth having an arc of from about 45 degrees to about 180 degrees were continually overlapped until a completed annulus or an arc of 360 degrees was formed. The annulus was then impregnated with a bonding agent and pyrolyzed to form a brake disk. Thus, a brake disk produced according to this patent had the same drawbacks as set forth immediately above and additionally required accurate overlapping of the various segmented cloths to achieve a relatively even distribution of weight as well as a constant disk thickness. In practice, the latter two aspects were often very difficult to achieve.
In order to reduce the time required for producing a carbon brake disk, Kovac et al, U.S. Pat. No. 3,956,548, constructed a thin or less-than-full width carbon core and applied wear disk layers to each side thereof via a carbon felt layer saturated with an adhesive. Naturally, upon pyrolyzation of the adhesive, an integral brake disk was formed. Although this construction reduced fabrication time, it still required substantial lamination of the various carbon cloth layers.
In U.S. Pat. No. 3,712,421 to Cook et al, a refurbishment technique is shown wherein once an existing carbon brake disk has been worn, it is ground down to a specific size, and previously laminated wear layers added either to one side or the other, or both.